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Wintry Palm Sunday NC and VA Winter Storm

Webberweather53 said:
If you wanted to see a stupid strong CAD dome, well you got it in the medium range. Think about the amount of easterly flow that the juxtaposition of this monster cold surface high in New England plus the combination of this "bomb" cyclone offshore will generate and pile mass like there's no tomorrow against the Appalachian mountains. The along barrier pressure gradient force is going to be mind-boggling as a result thus areas not accustomed to seeing sensible impacts from a CAD like north-central FL, Alabama, Tennessee, and Mississippi could get involved here. Even if you just like cold/snow, you have to appreciate the dynamics involved in extreme weather patterns like this.
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Just imagine this set up in January!
 
Only two things keeping snow out of areas SW of NC seems to be the elevation of the mountains. As soon as the mountains are shorter than the freezing layer at 850 or relative to them, it warms up drastically. In addition, the 700 layer is just out of reach. That's why there is ZR showing up since the 925 layer is quite chilly, around -4C at hour 90 across N GA gradually warming if it does Monday. However, I'm sure if the flow was stronger that the air could make it further south, but that's pushing it given the strength of the CAD already.

Also, if this becomes a legitimate threat for icing or sleet in NE GA, we may need to add it to the title.
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Nothing is written in stone yet, and probably won't be until the storm unfolds, but the trend has been a positive one today for winter weather around here.
 
packfan98 said:
Those are the type of storms where I get 1/2" to an inch of slop in NW Randolph County.
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Nobody cashes in on the slop,mixbag,transition line like we do. I lived in western part of county for 20 plus years. I've driven less than 5 miles from driveway into 5 inches before. But we are blessed cause we are always in the game from the coastals as well as the CADs. Never to far east or west to atleast get in on the fringes.
 
NW Piedmont fairs well on this run and even tries to get me back in the game.... hope it's a good start to the 0z suites
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Sounding for mby, I think I can work with this....

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Slow and steady improvement as we get closer. That's how we like it here.
 
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It's going to be too close to call southeast of the foothills and the extreme NW piedmont, there's no consistency between models from run-to-run on surface temps and arguably so since the timing of the CAD (both diabatic and synoptic) and precipitation rates will determine the amount of dynamical cooling and if surface temps are sufficient to support snow. These aren't processes the NWP models handle terribly well, a degree maybe two will make all the difference for areas like Raleigh, Asheboro, Roanoke Rapids, Rocky Mount-Wilson, Roxboro, Greensboro, and Winston-Salem and there's really no way of knowing if we'll go one way or the other until the event is almost upon us. The only areas that are really safe wrt precipitation type are the mountains.

As I mentioned yesterday wrt the UKMET, I don't even think you can go entirely to sleep on this in areas as far south as Charlotte and Fayetteville, and the Euro sure enough delivers some sct'd areas of wet snow/sleet even to upstate SC.
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The long term trend continues to favor a more suppressed and sheared wave, while that may be beneficial in pushing the heaviest axis of precipitation further SW, it also means that there's less heavy precipitation in general and we need heavy rates to go over to snow, this is a double edged sword in NC. However, there's still more than enough QPF in general to work with.
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Love seeing the south trend with the precip. I might be far enough north to eek out a couple of inches with this.
 
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Here’s my best guess for now, really tough call atm east of the mountains. I’m skeptical of the low level and surface modeled temps because there are going to be several processes that will act to continuously cool the sfc throughout the entire duration of the event. The combination of the fact that this event will be occurring at night so we will lose some outgoing IR to space, adiabatic cooling from layer lifting, melting hydrometeors aloft, sensible heat fluxes from snowflakes and cooler raindrops falling towards the sfc physically bringing colder air to the ground, and cold air advection at the surface with light northeasterly winds at the ground attributable to the in-situ cold air dam that will develop after the first precipitation falls. Models will almost assuredly miss the latter process as it relies on models to properly handle both the diabatic heating and the geostrophic adjustment that occurs as a result (good luck with that). Upward longwave IR fluxes from the ground and downward IR from clouds will attempt to offset these but the number and contribution of these processes should steadily cool the surface throughout the event. Aloft in the mid levels where condensation, deposition, as well as veering and WAA will be present is a different story
 
That's a good map, Webb. I'm disappointed that there seems to be less and less snow depicted farther east as we move forward in time. I guess that's because the wave is trending weaker? It would be better to see it go the other way. But the fact that we're even talking about it is a win, I guess.
 
Rain Cold said:
That's a good map, Webb. I'm disappointed that there seems to be less and less snow depicted farther east as we move forward in time. I guess that's because the wave is trending weaker? It would be better to see it go the other way. But the fact that we're even talking about it is a win, I guess.
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Thanks! This storm is a pain to forecast. Yeah that has a lot to do with it because a stronger wave would favor more intense precipitation and lifting however it would increase the WAA aloft over the in-situ CAD dome that’ll develop here.
My median expectation for Raleigh is mostly rain and possibly a quick burst of wet snow that doesn’t accumulate if we get under a nice band then we go back to rain which may mix with sleet at the end as the big high to our north noses in (Trace of sleet mixed with rain counts the same as moderate-heavy wet snow that doesn’t stick). The 0-1 range is a safe call for us and quite frankly the 0 is far more likely than the one. For the Triad I think a good middle of the road estimate is a trace or light dusting north of there towards the VA border is where you could see more substantial accums. Yeah the fact we’re even talking about this is a win in my book I mean how many years even have a glimmer of hope after mid March to get snow much less in the last week of the month within a week of Easter?
 
Hopefully, it will end up colder than the models show and we get more snow with heavy rates.
 
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